1. Field of the Invention
The present invention relates to dental or prophylaxis angles and, more specifically, to a disposable dental angle. Even more specifically, the present invention relates to a disposable dental angle having an angularly adjustable head.
2. Description of the Prior Art
Dental angles carry dental bits such as prophy cups and brushes, and burs. The angle enables dentists and hygienists more easily to reach the various surfaces of a patient's teeth. These angles generally include a body having a head thereon which has an axis that is angularly positioned with respect to an axis of the body. Typically, the angle of separation between the head and the body is 90.degree.. A drive gear and driven gear are supported within the body for enmeshing engagement to cause rotation of a dental bit that is carried by the driven gear. The body is normally slipped over the nose of a handpiece, such as a Doroit type handpiece, which has a collet that receives a shaft of the drive gear. The collet holds the shaft and connects the same to a motor which, upon operation, causes rotation of the shaft and the drive gear, and thus the driven gear with the dental bit.
Contra-angles are also used to carry dental bits; however, the contra-angles are particularly disposed for use in reaching difficult spots in a patient's mouth. Typically, the axis of the head is angled anywhere from 100.degree. to 120.degree. with respect to the axis of the body. To drive the driven gear that carries the dental bit, it is well known to use two drive shafts, one of which connects to the collet and the other of which connects to the driven gear. The two drive shafts are connected by intermediate gears that impart rotation to the driven gear upon rotation of the collet. Non-disposable contra-angles typically are quite complex and expensive;
however, the prior art contains two examples of disposable contra-angles.
U.S. Pat. No. 5,423,679, which issued to Ronald L. Bailey on Jun. 13, 1995, discloses in one embodiment a disposable prophylaxis contra-angle. The disposable prophylaxis contra-angle has a plastic body with its head fixed at an angular position which is about 15.degree. from the normal position. A one piece drive shaft and gear is made of a thermoplastic material, with a portion of the shaft being hollow to allow the shaft to bend as it rotates.
Another disposable contra-angle is disclosed in U.S. Pat. No. 5,433,605, which issued to Frederick P. Strobl, Jr., on Jul. 18, 1995. The disposable contra-angle has a body composed of two body components which are rotatably connected together with their respective axes offset by an angle of approximately 8.degree.-12.degree.. The first body component is disposed to attach to a collet of a drive unit, and the second body component rotatably attaches to the first body component for 360.degree. rotation thereon. Thus, while the angle of inclination is fixed, the angle is adjustable to a limited extent (i.e., .+-.8.degree.-12.degree.). A flexible drive shaft extends through the first and second components for driving a driven element and a dental bit. The drive shaft is made of a resilient thermoplastic material, and the shaft has a reduced diameter portion that allows the shaft to flex to the extent required. Furthermore, it is necessary for the thermoplastic material to have a tensile strength that exceeds the tensile stresses placed on the stretched side of the shaft.
Each of the above pieces of prior art utilize contra-angles which have a fixed angle of inclination. While the Strobl, Jr., device offers some adjustability by virtue of the rotatable connection, it does not offer an infinitely variable angle adjustment. Thus, the above contra-angles cannot possibly have a standard 90.degree. angle head position.
Other dental utensils have, however, been prepared so that they are capable of infinitely variable adjustments. One such device is disclosed in U.S. Pat. No. 5,150,495, which issued to Discko, Jr., et al. on Sep. 29, 1992. The device disclosed therein is a disposable bendable dental brush which has a bendable portion that comprises accordion-like folds. The accordion-like folds are rigid enough to allow the brush to be bent into an angular position, whereby the brush maintains the angular position until it is readjusted.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.